Technical Field
The present disclosure relates to an oil removal apparatus that removes oil particles (e.g., oil mist) contained in blow-by gas in an internal combustion engine.
Description of the Related Art
In a conventional technique employed in an internal combustion engine, blow-by gas is recirculated to an intake system from a crank case through a blow-by gas passage. An oil removal apparatus that removes oil particles contained in the blow-by gas is provided in the blow-by gas passage. Japanese Patent Application Publication No. 2005-334876, for example, discloses an electrostatic precipitator having a collector electrode that collects ionized oil mist within an electric field created by a pulse-driven high voltage corona discharge electrode.
Further, Japanese Patent Application Publication No. S61-133155 discloses an electrostatic purification apparatus that removes microparticulate matter contained in engine oil. The electrostatic purification apparatus is structured such that an insulating filter is provided between electrodes.
Furthermore, Japan Association of Aerosol Science and Technology vol. 14 No. 4, 338-347 (1999) discloses a microparticle removal unit used in a clean elevator of a clean room. This removal unit mainly removes microparticles believed to originate from oil using a dielectric filter method. The removal unit is structured such that a nonwoven fabric serving as a dielectric fiber layer is filled between an anode and a cathode of a parallel plate electrode. Dielectric polarization is generated in the nonwoven fabric by applying a voltage to the electrodes, and microparticles are collected in the nonwoven fabric using a dielectric polarization force that acts between the fibers and the microparticles in addition to Coulomb force acting on charged particles.